Containers made from laminates, such as those that include paperboard substrates, are known for use in storing beverages such as juice. Containers are designed to prevent oxygen from penetrating the containers to spoil the contents of the container. Further, pinholes present in a matte layer of the laminate may allow negative pressure in the headspace of the container to be released. This release may allow the container to bulge from its initial shape. Consumers may associate bulge of the container with spoilage of the goods inside of the container and with a defective product.
The sealing of containers is accomplished through the heating of the laminate and the application of pressure to the heated portions. Heating causes portions of the matte layer and/or gloss layer to melt. These melted portions are placed into engagement with additional portions of the laminate when the container is folded into a desired shape. The additional portions of laminate may themselves be melted or non-melted. Once cooled, a seal portion is formed such that the laminate may be sealed onto itself at a desired location. Over heating of the laminate may result in “over activation.” During such heating, water naturally associated with the substrate may be turned into steam. This steam may escape through the various layers of the matte layer and cause the pinholes to be formed in the matte layer and/or the gloss layer. As used herein, the term pinholes refers to blisters, bubbles, small holes, and other undesirable deformities brought about by the formation of the seal portion of the container through the application of heat to the laminate.
Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the invention.